Ubuntu 20.04 -- What are "stale online ext4 metadata check snapshots"

[bhubunt]

Here is what I get when I type in sudo lvdisplay

The LV status is available.

Can someone unpack what you see?

What does current LE mean?

I take it that the swap space is automatically part of the Ubuntu installation. See https://help.ubuntu.com/community/SwapFaq

Do I conclude from the code below that LVM is also automatically part of the Ubuntu 20.04 installation and can then be used by entering specific commands -- or not?

--- Logical volume ---
  LV Path                /dev/vgubuntu/root
  LV Name                root
  VG Name                vgubuntu
  LV UUID                VYh3ay-F9Ab-tb8G-2Oak-8a6Q-Tta5-dZTrWv
  LV Write Access        read/write
  LV Creation host, time ubuntu, 2023-03-31 12:46:27 +0200
  LV Status              available
  # open                 1
  LV Size                462,84 GiB
  Current LE             118488
  Segments               1
  Allocation             inherit
  Read ahead sectors     auto
  - currently set to     256
  Block device           253:1
   
  --- Logical volume ---
  LV Path                /dev/vgubuntu/swap_1
  LV Name                swap_1
  VG Name                vgubuntu
  LV UUID                KZAhTF-dCsA-Pbb1-r6V0-RJPH-j8d0-0Ptrcc
  LV Write Access        read/write
  LV Creation host, time ubuntu, 2023-03-31 12:46:27 +0200
  LV Status              available
  # open                 2
  LV Size                976,00 MiB
  Current LE             244
  Segments               1
  Allocation             inherit
  Read ahead sectors     auto
  - currently set to     256
  Block device           253:2

[maglin2]

Did you select encryption during installation?
(Edit - Long time since I installed 20.04, but looking back at the guide it suggests you have to select LVM to be offered Encryption, not the other way around, and you said in #3 you didn't activate LVM).

[#&thj^%]

Did you select encryption during installation?

+1

What does current LE mean?

You almost had me on that one, had to have a second cup of coffee for that one.
Meaning:"logical extent (LE)", Each logical volume is split into chunks of data, known as logical extents. The extent size is the same for all logical volumes in the volume group.
Or as (PE) physical extent (PE)
if you use certain back-up tools LMV could be pulled in.

Do I conclude from the code below that LVM is also automatically part of the Ubuntu 20.04 installation and can then be used by entering specific commands -- or not?

I'm not certain on this one, but as said>>certain back-up tools LMV could be pulled in.
EDIT: Just confirmed, depending on environments on your initial Install, it looks like it is used.

Package: lvm2
Version: 2.03.16-1ubuntu1
Priority: optional
Section: admin
Origin: Ubuntu
Maintainer: Ubuntu Developers <ubuntu-devel-discuss@lists.ubuntu.com>
Original-Maintainer: Debian LVM Team <team+lvm@tracker.debian.org>
Bugs: https://bugs.launchpad.net/ubuntu/+filebug
Installed-Size: 4,162 kB
Pre-Depends: init-system-helpers (>= 1.54~)
Depends: libaio1 (>= 0.3.93), libblkid1 (>= 2.24.2), libc6 (>= 2.34), libdevmapper-event1.02.1 (>= 2:1.02.74), libedit2 (>= 2.11-20080614-0), libselinux1 (>= 3.1~), libsystemd0 (>= 233), libudev1 (>= 183), systemd | systemd-tmpfiles, lsb-base, dmsetup (>= 2:1.02.185-1ubuntu1~), dmeventd (>= 2:1.02.185-1ubuntu1~)
Recommends: thin-provisioning-tools
Homepage: https://sourceware.org/lvm2/
Task: server-minimal, cloud-image, ubuntu-live, server, ubuntu-server-raspi, kubuntu-live, xubuntu-live, lubuntu-live, ubuntustudio-dvd-live, ubuntukylin-live, ubuntu-mate-live, ubuntu-budgie-live, ubuntu-unity-live, edubuntu-dvd-live, edubuntu-server-raspi
Download-Size: 1,187 kB
APT-Manual-Installed: yes
APT-Sources: http://archive.ubuntu.com/ubuntu lunar/main amd64 Packages
Description: Linux Logical Volume Manager
 This is LVM2, the rewrite of The Linux Logical Volume Manager.  LVM
 supports enterprise level volume management of disk and disk subsystems
 by grouping arbitrary disks into volume groups. The total capacity of
 volume groups can be allocated to logical volumes, which are accessed as
 regular block devices.

N: There is 1 additional record. Please use the '-a' switch to see it

And we know already I use it:

apt policy lvm2
lvm2:
  Installed: 2.03.16-1ubuntu1
  Candidate: 2.03.16-1ubuntu1
  Version table:
 *** 2.03.16-1ubuntu1 500
        500 http://archive.ubuntu.com/ubuntu lunar/main amd64 Packages
        100 /var/lib/dpkg/status
     2.03.11-2.1ubuntu4 500
        500 http://us.archive.ubuntu.com/ubuntu jammy/main amd64 Packages

[bhubunt]

Did you select encryption during installation?
(Edit - Long time since I installed 20.04, but looking back at the guide it suggests you have to select LVM to be offered Encryption, not the other way around, and you said in #3 you didn't activate LVM).

Yes, I did. Problem solved.

[bhubunt]

+1


You almost had me on that one, had to have a second cup of coffee for that one.

Yes, indeed, I selected encryption --

That also explains why
e2scrub_reap.service

is on my system, getting rid of those pesky stale online ext4 metadata check snapshots
(what a mouthful)

[#&thj^%]

(what a mouthful)